The long term objective is to understand the mechanism of the chemomechanical cycle of molecular motors during which the energy from ATP hydrolysis is transferred into mechanical movement. Members of kinesin superfamily move along microtubules and are involved in important functions, such as organelle transportation and chromosome segregation. Since kinesin motors may play important roles in cell division, they represent potential drug targets for cancer chemotherapy. Mechanistic and biological investigations of these molecules should be valuable for drug design studies in the future. The experiment will concentrate on mutants of kinesin motors to test if the "neck-linker" region is important in force generation and also how the microtubule binding affinity affects maximum force motor can exert and power stroke made by kinesin monomer constructs. High resolution optical trapping microscopy will be used to measure the force and step size of the motors.